1. Field of the Invention
The teachings provided herein generally relate to formulations and uses of extracts of Curcuma longa L. plants for safe use topically, orally, rectally, or vaginally, for example.
2. Description of Related Art
A New Use of Curcuma longa L. Extract as a Sunscreen
The teachings provided herein shows that the Curcuma longa L. extract, surprisingly, has very good ultraviolet energy absorption properties across the entire wavelength range of interest, making it very attractive as a sunscreen agent. Moreover, the constituents of Curcuma longa L. have been shown to provide other therapeutic benefits. For example, antioxidant and anti-inflammatory effects have been shown, and treatments for Alzheimer's disease, Parkinson's disease, cystic fibrosis, liver injury, alcohol-induced liver disease, multiple sclerosis, human immunodeficiency virus (HIV), and cancer have been proposed. As such, the use of Curcuma longa L. extract as a sunscreen agent has the potential of providing additional therapeutic benefits that could far exceed merely protecting the skin from the UV rays of the sun.
There are clearly many sunscreen products on the market, and all utilize chemical agents to absorb UV radiation. UV radiation is the radiation that has shorter wavelengths than visible light and ranges from about 10 nm to 400 nm. The lower wavelengths, up to about 290 nm, are screened out by the earth's ozone layer and are generally of less interest. As such, sunscreen products focus on wavelengths ranging from 290 nm to 400 nm. Wavelengths ranging from 290 nm to 320 nm are considered “UVB” rays, and although UVB rays have a higher intensity, they also have less penetration power. As such, UVB rays may damage the superficial layers of skin but do not penetrate deeper, they do not penetrate glass, and their effects can generally be felt greatest between the hours of 10 a and 4 p in the US. Wavelengths ranging from 320 nm to 400 nm are considered “UVA” rays. UVA is less intense but penetrates deeper into the skin to cause damage to the deeper layers, through glass, and its effects are not limited to certain hours of the day. UVA has been considered to be less damaging than UVB due to it's lower intensity, and because UVB light has been identified as primarily responsible for sunburn, as well as melanoma and other skin cancers. However, UVA/s ability to cause damage at deeper layers of the skin, and because it's about 30 to 50 times more prevalent than UVB, much attention has recently been focused on UVA radiation. It has been shown, for example, that UVA can potentiate carcinogenesis from UVB and affects immune function. Interestingly, on Jun. 17, 2011, the FDA reported that sunscreen products should have both UVA and UVB protection, and that the UVA range has two unique areas of interest, the UVA1 area ranging from 340 nm to 400 nm and the UVA2 area ranging from 320 nm to 340 nm. The FDA stated that too much emphasis has been placed on UVB, that at least 20% of the protection should be in the UVA2 region, and at least 60% of the protection should be in the UVA1 region, stressing that the UVA1 region is important.
A problem is that currently available sunscreen chemicals absorb light in either the UVA or UVB range. As such, the desired level of protection for the consumer, as indicated by at least the FDA, is not readily available. Currently, to address this problem, the art uses (i) titanium dioxide to extend the UVA range of protection, (ii) a combination of sunscreen agents to overlap and broaden the spectrum of UV protection, or (iii) a combination of titanium dioxide and overlapping ranges. Significant problems still remain, however. One problem is that the overlapping of peaks leaves skin exposed to weak protection in areas of the UV spectrum due to an inability to adequately overlap protection across the UV spectrum. Another problem is that the titanium dioxide can penetrate the skin, and this makes it particularly problematic in that it can potentially convert to compounds that pose a cancer risk when exposed to the UV energy.
The Problems of Producing a Curcuma longa L. Extract
Extraction methods that currently exist suffer several problems. One problem is that these methods incorporate undesirable chemicals at undesirable levels, for example, ethylene dichloride, methylene dichloride, and ethyl acetate. Ethanol can also be used, but it can only be present to a limited extent for internal consumption, and topical application is also limited due to side effects. As such, much effort has been spent trying to keep residual solvents below limits. Current extraction processes, for example, generally require complex processes that include removal of undesirable or toxic extraction solvents to meet FDA rules, and this can include, for example, distillation of the solvent to form a powder of the extract, a back-extraction of the extract into a different solvent that is suitable for a particular use, complexing with metal ions, use of high pH to precipitate a complex with ammonia, washing with methanol and water, and drying at high temperatures. In view of at least the above, current extraction methods suffer from (i) use of toxic solvents that require steps to remove and risk the presence of toxic residuals; (ii) heating in multiple steps to extract and purify; (iii) use of a high pH up to 9.5 on Curcuma longa L., which degrades above pH 7.0; and, ipso facto (iv) multi-step processes that are complex and expensive. There is currently no extraction process for Curcuma longa L. that uses a solvent that is suitable for both topical use and internal consumption.
Improving the Use of Curcuma longa L. Extract in Other Administrations, Such as Oral or Rectal Administrations
Herbal preparations, including Curcuma root, are offered commercially, usually as capsules containing the dried and ground plant material. Curcuma longa L. can be used as an antioxidant, as a free radical scavenger, to remove reactive oxygen species (ROS) implicated in many diseases, making these species unavailable to human tissues. It can also be used as an antiflammatory. A problem is that the current preparations are typically large in order to obtain a desired dosage, or multiple capsules have to be taken, resulting in an inconvenience to the consumer and, of course, non-compliance. Stable, concentrated formulations, such as solutions, emulsions, microemulsions, and nanoemulsions, would be appreciated by those skilled in the art in order to increase compliance of administration, as well as the bioavailability, of the components of the extract after administration.
One of skill in the art will appreciate having (i) a sunscreen with a very broad band of absorption with desired strength across the UVA and UVB ranges without requiring the addition of titanium dioxide. In addition, the art would appreciate having (ii) a process of producing the extract without requiring the removal of the extraction solvent, reducing complexity and cost of processing. Moreover, the art would also appreciate (iii) an antioxidant dosage form that not only can be used directly from the extraction process, but also is potent and concentrated to a smaller quantity for consumption for increased compliance with a variety of administrations and uses. In particular, the art would appreciate having (iv) microemulsion and nanoemulsion formulations that can be easily produced directly from the extraction process without requiring further separation of extraction solvents, the emulsions providing an enhancement to the bioavailability of the extracts as well as an increased stability. And, the art would also appreciate having (v) extract formulations that can be used in combination as a topically, orally, and/or rectally administered composition for the variety of indications taught herein. Finally, the art will appreciate having extraction methods that can provide all of the above while also providing (vi) an extraction process having a significantly higher yield than state-of-the-art processes.